In tri-panel DLP applications, total internal reflection (TIR) prisms are used to change the light path of DLP devices, thereby reducing the size of the DLP devices. Such TIR prisms typically include two triangular prisms arranged such that the hypotenuse surfaces thereof are glued to each other, but a space is left in between. The triangular prism is typically made of glass, which is suitable for coating. However, it is difficult to shape these glass prisms accurately (requiring accuracy in the cutting, grinding, and polishing processes), and therefore production yield is extremely low.
Therefore, it is desirable to provide a prism system, which can overcome the above mentioned problem.